The Catacombs of Paris are truly unique. Remains of about 6 million people, stretching for kilometers.
By fact the largest cemeteries in the world occupying the remains of quarries and tunnels dug to extract the famous stone with which were constructed buildings and cathedrals.

The problem to shoot inside the catacombs is big, is forbidden to use the flash and also the tripod.
The only light are week lamps on the walls. So ISO to the maximum possible, lean against the wall, very firm hand, iris wide open and as always a lot of patience. If I could do something I with my Canon 450D can succeed too.